# PrePoMax in the RR3 Wind-Turbine Tower Benchmark (Sadowski Round Robin 2024–2025) – Results & Observations

**URL:** <https://prepomax.discourse.group/t/prepomax-in-the-rr3-wind-turbine-tower-benchmark-sadowski-round-robin-2024-2025-results-observations/3049>\
**Category:** Tips & Tricks\
**Created:** [November 3, 2025, 9:44am UTC](https://prepomax.discourse.group/t/prepomax-in-the-rr3-wind-turbine-tower-benchmark-sadowski-round-robin-2024-2025-results-observations/3049 "2025-11-03T09:44:04Z")\
**Posts on this page:** 1\
**Showing post:** 26

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**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\
**Post date:** [November 9, 2025, 9:47am UTC](https://prepomax.discourse.group/t/prepomax-in-the-rr3-wind-turbine-tower-benchmark-sadowski-round-robin-2024-2025-results-observations/3049/26 "2025-11-09T09:47:36Z")

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> [@hnrwagner](#):
>
> I just removed the rigid body constraint from the bottom, thats it nothing else

Yeah, it’s just that nasty “rigid body + Nlgeom + shells = non-convergence” limitation of CalculiX. It’s explained by the CalculiX dev here: [Rigid-body constraint convergance problems - #25 by dhondt - CalculiX (official versions are on www.calculix.de, the official GitHub repository is at https://github.com/Dhondtguido/CalculiX).](https://calculix.discourse.group/t/rigid-body-constraint-convergance-problems/369/25)

Here you can find a list of various CalculiX limitations with workarounds: [Known CalculiX limitations](https://prepomax.discourse.group/t/known-calculix-limitations/3050)

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